Definition of sericite in English:

noun

The samples from the andesitic units, occurring as tectonic lenses in the greywacke sequence, exhibit plagioclase phenocrysts altered to sericite, calcite and epidote, set in a matrix of chloritized pyroxene and amphibole.

The nearby K - 2 deposit is very similar to the Kettle and contains, besides quartz, veins with calcite, ferroan dolomite, and minor chlorite, potassium feldspar, adularia, sericite, pyrite, and barite.

Many of the grains are partially to entirely replaced by fine-grained sericite and quartz.